Telescopic spectacles are used by surgeons and others who must work with minute objects. Typically the telescopes are arranged either in pairs, with one telescope positioned for viewing by each eye of the wearer, or alternatively, with a single telescope positioned in the center of the spectacles. The image path from the single telescope is divided into two images, with one image being viewed by each eye. Telescopic spectacles may be constructed either with or without an integral object illuminator.
When the illumination, either supplied by a light source which is integral with the telescopic spectacles or otherwise provided externally, does not illuminate the object to be viewed along the viewing image path, portions of the object in the light path cast shadows. The casting of shadows increases the difficulty in viewing other portions of small objects, for example within an operating field. Shadows are least when the illumination beam and the viewing image path are coaxial and they increase in size as the angle of divergence between the illumination beam and the viewing image path increases.
Examples of providing the illumination and the image viewing path coaxial by using beamsplitters are shown in the commonly assigned applications Ser. No. 07/419,896, filed Oct. 11, 1989 and Ser. No. 07/419,761, filed Oct. 11, 1989. The present invention discloses a coaxial illuminator which permits illumination of an object along the image viewing path while reducing the amount of light reflected into the eyes of the user.